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GENESIS AND STRUCTURAL PROPERTIES OF (Ce1–xMx0.8Ni0.2Oy (M = La, Mg) OXIDES
Journal of Structural Chemistry ( IF 1.2 ) Pub Date : 2020-07-01 , DOI: 10.1134/s0022476620070100
E V Matus , I Z Ismagilov , V A Ushakov , A P Nikitin , O A Stonkus , E Yu Gerasimov , M A Kerzhentsev , P Bharali , Z R Ismagilov

The genesis and structural properties of (Ce1–xMx)0.8Ni0.2Oy (M = La, Mg; x = 0, 0.2, 0.5, 0.8, 1; 1.0 ≤ y ≤ 1.8) oxides that are promising catalyst precursors are studied. A complex of physicochemical methods (low-temperature nitrogen adsorption, ex situ and in situ powder X-ray diffraction, electron microscopy, Raman spectroscopy, and EDX analysis) is used to show that after the calcination at 500 °C in the oxidizing medium, (Ce1–xMx)0.8Ni0.2Oy become mesoporous materials representing substitutional solid solutions with a cubic fluorite-type structure with supported particles of the Ni-containing phase. When M = La, Ni cations are mainly stabilized in the composition of the Ce–La–Ni–O solid solution, and when M = Mg, they are stabilized in the Mg–Ni–O composition. It is found that La- or Mg-containing samples, as compared to Ce0.8Ni0.2Oy, have highly defective structures and smaller sizes of crystallites (≤ 4 nm, x ≥ 0.5). After thermal treatment of the samples in H2/Не at 800 °C, highly dispersed Ni° particles with a size of 5-10 nm are formed. Metal particles have defects and a polycrystal structure, and they are readily reoxidized in air with the formation of “core@shell” Ni@NiO structures.

中文翻译:

(Ce1–xMx0.8Ni0.2Oy (M = La, Mg) 氧化物的成因和结构特性

研究了 (Ce1–xMx)0.8Ni0.2Oy (M = La, Mg; x = 0, 0.2, 0.5, 0.8, 1; 1.0 ≤ y ≤ 1.8) 氧化物的起源和结构特性,这些氧化物是有前景的催化剂前体。综合物理化学方法(低温氮吸附、异位和原位粉末X射线衍射、电子显微镜、拉曼光谱和EDX分析)表明,在氧化介质中500°C煅烧后, (Ce1–xMx)0.8Ni0.2Oy 成为代表置换固溶体的介孔材料,具有立方萤石型结构和含镍相的负载颗粒。当 M = La 时,Ni 阳离子主要稳定在 Ce-La-Ni-O 固溶体的组成中,当 M = Mg 时,它们稳定在 Mg-Ni-O 组成中。发现与 Ce0.8Ni0.2Oy 相比,含 La 或 Mg 的样品,具有高度缺陷的结构和较小尺寸的微晶(≤ 4 nm,x ≥ 0.5)。样品在 H2/Не 中在 800 °C 下热处理后,形成了高度分散的 Ni° 颗粒,尺寸为 5-10 nm。金属颗粒具有缺陷和多晶结构,它们在空气中很容易再氧化,形成“核@壳”Ni@NiO 结构。
更新日期:2020-07-01
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